Reproducing PROFINET in the Lab: Discovery, AR Establishment, and Cyclic RT Boundaries
DCP provides Layer 2 discovery and configuration functions. LLDP contributes neighboring-device and topology information. DCE/RPC over UDP port 34964 carries acyclic application-relation traffic, including structures associated with AR and IOCR configuration. Cyclic Real-Time communication uses PROFINET’s EtherType, 0x8892, and carries process data directly over Ethernet. These components are connected. Discovery identifies a device, but discovery […]
GPT-6 Astra Is Not Just a Smarter Model. It Is a Computer Operator.
The published API envelope is substantial: Property GPT-6 Astra Input Text and images Output Text Context window 1,050,000 tokens Maximum input 922,000 tokens Maximum output 128,000 tokens Knowledge cutoff April 30, 2026 Reasoning effort low, medium, high, xhigh, max Main APIs Responses, Chat Completions, Batch The Responses API supports web search, file search, image generation, […]
Cómo armé un Pit Wall con AWS IoT Core (y por qué este patrón sirve para cualquier industria)
Fijate lo que no puede hacer este certificado: no puede publicar en sim/pit-wall-sim-02/telemetry (el topic de otro simulador), y no puede suscribirse a nada que no sea su propio topic de comandos. Si mañana alguien clona el certificado de un simulador, el radio de daño queda contenido a ese único dispositivo — nunca escala al […]
Deep Learning and Transformers
Each input is associated with a weight: w₁, w₂, …, wₙ The neuron calculates a weighted sum: z = Σᵢ wᵢxᵢ + b where b is called the bias. The result then passes through an activation function: a = f(z) In vector notation, we can write the same basic idea as: z = w · […]
Your robots.txt might not say what you think it says
I ship a bunch of small free tools, and last week I wanted a quick way to double-check what robots.txt a site was actually serving to crawlers — not what’s sitting in the repo, what’s actually on the wire. Turns out those aren’t always the same thing. Cloudflare has a feature called AI Crawl Control […]
The Remote Job Printed Nothing for 48 Hours. stdout Had No TTY.
Run it two ways before you touch pytest, Docker files, or an agent prompt. python reproduce_buffer.py python reproduce_buffer.py | cat python -u reproduce_buffer.py | cat PYTHONUNBUFFERED=1 python reproduce_buffer.py | cat On a laptop TTY, the first command prints starting batch immediately, then sleeps, then raises RuntimeError. Piped through cat, that same print often stays hidden […]
If Your Agent Wrote the Test, Ignore the Green Build
Do not hide fixtures inside pytest helpers. Pytest may wrap the grader later. It must not replace the oracle files. Human-written cases { “cases”: [ { “id”: “refund-partial-usd”, “input”: { “order_id”: “ord_1001”, “paid_cents”: 5000, “refund_cents”: 1200, “currency”: “USD” }, “expect”: { “status”: “ok”, “refunded_cents”: 1200, “remaining_cents”: 3800 } }, { “id”: “refund-overpay-rejected”, “input”: { “order_id”: […]
Why your Amazon payouts never match per order (and how to reconcile the FX gap)
If you sell on a marketplace whose currency differs from your bank’s, you have probably tried to compute, per order, how much you will actually be paid — and found that the numbers never tie out. Here is why, and the reconciliation approach that does tie out to the cent. The SP-API does not expose […]
Free Tools Every Competitive Programmer Should Bookmark
If you’ve ever lost 20 minutes at 2 AM debugging a submask enumeration loop, or drawn a segment tree on paper for the fifth time this month, this post is for you. I want to share a collection of 31 free, browser-based tools built specifically for competitive programming — no signup, no installs, code stays […]
OpenBSD Stories: Strange Medieval Devices
The Problem & Industry Shift The OpenBSD project is renowned for its security focus, but its hardware support philosophy is equally distinctive: it actively supports a vast array of obscure and obsolete devices, some of which feel like relics from a medieval technological era. While mainstream OSes drop support for legacy hardware to reduce maintenance […]